Question

I want to parse certain information from given patterns, which are as follows:

/root/test/subfolder/
relative/folder/
index.html
/root/test/style.css
test/test2/test3/testN/

I created a regex but it doesn’t match multiple strings like root/, test/ only the last instance. My code:

Regex re = new Regex(@"^(/?)([\w\.]+/)*([\w\.]+)?$");

foreach (Group gr in re.Match("/templates/base/test/header.html").Groups)
  Console.WriteLine(gr + " @ " + gr.Index.ToString());

Console.ReadKey();

I want to have first slash as optional, then path with / at the end and optional filename at the end.

Answer 1

Repeated capturing groups always capture only the last repetition. But you can capture the entire repeated group instead (and use non-capturing parentheses (?:...) for the repeated group:

 Regex re = new Regex(@"^(/?)((?:[\w\.]+/)*)([\w\.]+)?$

This will work in other regex flavors, too. .NET offers another feature, though: It is possible to access the individual matches of a repeated capturing group. Using your regex:

Match match = Regex.Match(input, @"^(/?)([\w\.]+/)*([\w\.]+)?$");
foreach (Capture capture in match.Groups[2].Captures) {
    Console.WriteLine("      Capture {0}: {1}", captureCtr, capture.Value);
    captureCtr += 1;                  
}